Let’s say that life in the galaxy is not common, but very rare. Now let’s say that we find an Earth sized planet in the habitable zone around a sun like star, and it’s completely lifeless. What would be the barest number of species needed to allow Humans to live on that planet? Which organisms would you seed the planet with if you only had room for 1,000 species?

Earth’s energy balance can be tipped one way or another depending on the amount of energy input and/or output. How great the energy increase or decrease must be, to make a significant difference in our lifestyle is still somewhat of a mystery.
Although, the following web site has some information on the subject:
[http://www.giss.nasa.gov/research/news/20050428/]
“The present planetary energy imbalance is large by standards of Earth’s history. For example, an imbalance of 1 Watt per square meter maintained for the last 10,000 years is sufficient to melt ice equivalent to 1 kilometer of sea level (if there were that much ice), or raise the temperature of the ocean above the thermocline (the boundary layer between the warm, surface waters and the deep ocean) by more than 100°C”

Nuclear reactions are very energetic, for instance information from this site says:
[http://www.giss.nasa.gov/research/news/20050428/]
“A kilogram of uranium-235 (U-235) converted via nuclear processes contains approximately three million times the energy of a kilogram of coal burned conventionally (7.2 × 10^13 joules per kilogram of uranium-235 versus 2.4 × 10^7 joules per kilogram of coal.”

From the web site: [http://www.ibtimes.com/articles/122432/20110314/japan-earthquake-nuclear-reactor-us-fukushima-daiichi-radiation-chernobyl-meltdown-explosion.htm]
The information is that:
“–US is the world’s largest producer of nuclear power-based electricity, producing 838 TWh (terawatt hour) which is 30.7 percent of the world total of 2731 TWh.

Since power conversions are never 100 percent efficient, it means that if 2731 TWh of electrical energy is being generated, then there must be more than that amount of energy being released into the environment in the form of heat. All the electrical energy generated this way will eventually convert to heat and will dissipate into the environment, so if the figure of 2731 TWh is all converted to heat energy and if that figure represents only one third of the total generated energy, then the nuclear power plants alone produce 2731 * 3 = 8193 TWh worth of heat energy.
(8193 Twh = 2.949*10 to the 19th power of joules.)

Now, add to that all the heat energy produced by burning fossil fuels and the total quantity will be much larger.

Information from: [http://en.wikipedia.org/wiki/Earth%27s_atmosphere] indicates that the mass of the atmosphere is about 5 quadrillion (5×10^15) tonnes.
To put the scale into mathematical perspective: 2.949*10^19 / 5*10^15 = 5898

In other words 2.949*10^19 joules of energy divided by the number of tons of air 5*10^15 = 5898 joules of energy per ton of air per hour is inserted into the atmosphere.
5898 joules = 1.639 Watt hours or 5.59 BTU.

So, the energy input from only all the nuclear power plants in the world would be enough to heat the quantity of atmospheric gasses over time, if that energy did not radiate into space, but the story does not end there.

From Scientific American January 26, 2009
http://www.scientificamerican.com/article.cfm?id=nuclear-waste-lethal-trash-or-renewable-energy-source&page=3
It states that:
“as much as 95 percent of the energy in fissile uranium remains in the waste.”

If the above figure of 8,193 TWh is only 5% of the total energy that will convert to heat energy, then the total heat energy production from nuclear power plants alone is 163 860 TW per hour, and that is equivalent to 5.899*10^20 joules.

The quantity of 163 860 TWh is approximately 0.94 times the total energy from the sun that hits the Earth.
No wonder the globe is warming, we are adding almost another sun‘s worth of energy to it.

According to the laws of physics, energy can not be created or destroyed, so that any energy that we convert from stored/potential energy into kinetic energy must manifest itself as an increase in the molecular motion of the materials in the immediate vicinity, from there it can be dissipated further by conduction, convection or radiation.

The planet Earth can lose heat energy in two different ways, one is that of radiation, and the other can be compared to convection and/or evaporation.
It is a fact that hot air rises, if air molecules obtain greater kinetic energy from any source, then they will tend to rise higher in the atmosphere, the more energy they have the higher they go, if the kinetic energy of the molecules is extremely high, (about 7 miles per second.) then the molecules can escape Earth’s gravitational field and in that way they can take the kinetic energy (heat) with them to outer space.

Is the ozone layer disappearing into space, instead of being destroyed by heavy molecules such as CFC’s?
It’s not only at the south pole where the ozone disappears?
http://www.theozonehole.com/arctic2001loss.htm

When the temperature gets to the point where snow doesn’t melt in the summer, it takes a shockingly short time – sometimes only decades – for the Ice to start moving in.